H3C Technologies H3C WX3000E Series Wireless Switches - Manual (Page 34)

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• Class-one configurations do not affect the aggregation state of the member port even if they are
different from those on the aggregate interface. GVRP and MSTP settings are examples of class-one
configurations.
NOTE:
The class-one configuration for a member port is effective only when the member port leaves the
aggregation group.
Reference port
When setting the aggregation state of the ports in an aggregation group, the system automatically picks
a member port as the reference port. A Selected port must have the same port attributes and class-two
configurations as the reference port.
LACP
The IEEE 802.3ad Link Aggregation Control Protocol (LACP) enables dynamic aggregation of physical
links. It uses link aggregation control protocol data units (LACPDUs) for exchanging aggregation
information between LACP-enabled devices.
1. LACP functions
The IEEE 802.3ad LACP offers basic LACP functions and extended LACP functions, as described in Table
3 .
Table 3 Basic and extended LACP functions
Category Description
Basic LACP functions
Implemented through the basic LACPDU fields, including the system LACP priority,
system MAC address, port aggregation priority, port number, and operational key.
Each member port in a LACP-enabled aggregation group exchanges information
with its peer. When a member port receives an LACPDU, it compares the received
information with the information received on the other member ports. In this way the
two systems reach an agreement on which ports should be placed in the Selected
state.
Extended LACP
functions
Implemented by extending the LACPDU with new Type/Length/Value (TLV) fields.
2. LACP priorities
LACP priorities have the following types: system LACP priority and port aggregation priority, as
described in
Table 4 .
Table 4 LACP priorities
Type Description Remarks
System LACP
priority
Used by two peer devices (or systems) to determine which one is
superior in link aggregation.
In dynamic link aggregation, the system that has higher system LACP
priority sets the Selected state of member ports on its side first and then
the system that has lower priority sets port state accordingly.
The smaller the
priority value,
the higher the
priority.
Port aggregation
priority Determines the likelihood of a member port to be selected on a system.
The higher port aggregation priority, the higher likelihood.